Abbreviation: ActLat
An \emph{action lattice} is a structure $\mathbf{A}=\langle A,\vee,\wedge,0,\cdot,1,^*,\backslash ,/\rangle$ of type $\langle 2,2,0,2,0,1,2,2\rangle$ such that
$\langle A,\vee,0,\cdot,1,^*\rangle$ is a Kleene algebra
$\langle A,\vee,\wedge\rangle$ is a lattice
$\backslash$ is the left residual of $\cdot $: $y\leq x\backslash z\Longleftrightarrow xy\leq z$
$/$ is the right residual of $\cdot$: $x\leq z/y\Longleftrightarrow xy\leq z$
Let $\mathbf{A}$ and $\mathbf{B}$ be action lattices. A morphism from $\mathbf{A}$ to $\mathbf{B}$ is a function $h:A\rightarrow B$ that is a homomorphism:
$h(x\vee y)=h(x)\vee h(y)$, $h(x\wedge y)=h(x)\wedge h(y)$, $h(x\cdot y)=h(x)\cdot h(y)$, $h(x\backslash y)=h(x)\backslash h(y)$, $h(x/y)=h(x)/h(y)$, $h(x^*)=h(x)^*$, $h(0)=0$, $h(1)=1$
Example 1:
Classtype | variety |
---|---|
Equational theory | |
Quasiequational theory | undecidable |
First-order theory | undecidable |
Locally finite | no |
Residual size | unbounded |
Congruence distributive | yes |
Congruence modular | yes |
Congruence n-permutable | yes, $n=2$ |
Congruence regular | no |
Congruence e-regular | yes |
Congruence uniform | no |
Congruence extension property | no |
Definable principal congruences | no |
Equationally def. pr. cong. | no |
Amalgamation property | |
Strong amalgamation property | |
Epimorphisms are surjective |
$\begin{array}{lr}
f(1)= &1
f(2)= &1
f(3)= &3
f(4)= &20
f(5)= &149
f(6)= &1488
\end{array}$